1. Field
The present invention relates to a vacuum sealing gasket structure and more particularly to a vacuum sealing gasket structure where a gasket can be rapidly secured in a gland without adhesive and a treatment tool utilizing the gasket structure.
2. Description of the Related Art
In a casting process, objects are formed in a casting machine by adding liquid casting material to a forming tool. The forming tool includes a casting space, the shape of which corresponds to the shape of the object. The forming tool usually includes two halves, where one side is movable and the other is fixed. The forming tool is usually equipped with cooling members such as cooling flanges or cooling channels. The object is kept in the forming tool until it has cooled sufficiently in order to, for example, be transported on a conveyor belt and still keep its shape. When the object is sufficiently cooled to allow further treatment, the forming tool is opened by moving the movable side to the side and the object is picked out of the casting machine. Thereafter, the next object can be cast.
The time it takes to cast an object is called the cycle time, and the cycle time determines the number of objects that can be produced per time unit. For casting processes producing large volumes, short cycle times are important in order to produce as much as possible. To reduce cycle times down has proven to be difficult in view of physical obstacles, such as that the forming tool must reach a certain temperature before the casting material can be added to the forming tool and that the object must be cooled in the forming tool in order to keep its exact shape. If the object is moved too early from the forming tool, there is a risk of skew, dimensional deviations cracking and deformation created from the ejectors pine. However, the cycle time has been decreased by optimizing the time for closing, filling, cooling, opening and ejection. An essential part of the cycle time is constituted by the time for cooling the object, the cooling time, which has as its only purpose to secure the objects dimensional accuracy and quality. In certain casting processes, the cooling time can be up to 70-80% of the total cycle time.
Recently, a device and method for thermal treatment that reduces total cycle time has been proposed in International Publication No. WO 01/78970. In International Publication No. WO 01/78970, it has been proposed to transport the object from the forming tool to a treatment tool, which includes a treatment surface, the shape of which at least in some parts imitates the casting space and is arranged outside the casting machine, so that some of the time for cooling can take place outside the casting machine, which in turn means that the cycle time is shortened.
In International Publication No. WO 01/78970, the treatment tool includes a vacuum tube to connect the object to the treatment tool in order to pull the object out of the casting space and further to prevent the object from falling out of the treatment tool during the transportation from the forming tool. In order to maintain the seal of the vacuum between the object and the treatment tool, a gasket surrounds a periphery of the treatment tool.
However, when used with the treatment tool, a conventional gasket has numerous disadvantages. For example, due to the temperatures, chemical and mechanical degradation while the device handles the object, a conventional silicone rubber gasket has a short lifespan and also must be glued into the track. In view of the short lifespan of the gasket and the complicated process removing a glued-in gasket, cleaning the gasket glue surfaces, applying glue to a new gasket, and installing the new gasket, a conventional device for thermal treatment such as disclosed in International Publication No. WO 01/78970 is subject to significant down time.